Learn Hardcore Croatian: Molim vas, pošaljite e-mail sutra ujutro.

Molim vas: polite/formal; used with respectful singular “you” (Vi) or with more than one person.
Molim te: informal; to friends, family, peers.
Molim (alone): can mean “please,” “you’re welcome,” or “pardon?/what?” (e.g., on the phone). For polite requests, Molim vas is the safest choice.

Why is there a comma after Molim vas?

Because Molim vas is an introductory polite phrase. Standard punctuation sets it off with a comma: Molim vas, pošaljite… Without the comma it’s still understandable, but the comma is preferred in writing.

Why is it pošaljite and not pošalji?

Pošaljite is the imperative for second person plural, used for addressing multiple people or for polite singular “you.” Pošalji is singular informal. So for a respectful request to one person, pošaljite is correct.

Which verb is this from, and what about aspect? Pošaljite vs šaljite?

Pošaljite comes from the perfective verb poslati (send once/complete the action).
Šaljite comes from the imperfective slati (send repeatedly/continuously). Here, you want a single completed action, so pošaljite is natural.

Can I say Molim vas da pošaljete e-mail sutra ujutro instead?

Yes. Molim vas, pošaljite… (imperative) and Molim vas da pošaljete… (da-clause) are both correct. The da-clause is slightly more indirect/formal in tone; the imperative is direct but still polite.

Can I move sutra ujutro elsewhere in the sentence?

Yes. All of these are fine:

Molim vas, pošaljite e-mail sutra ujutro.
Molim vas, pošaljite sutra ujutro e-mail.
Molim vas, sutra ujutro pošaljite e-mail. Moving sutra ujutro earlier gives it more emphasis.

Is sutra ujutro redundant? Why both words?

It’s standard, just like English “tomorrow morning.” Sutra = tomorrow; ujutro = in the morning. Together they specify the time unambiguously.

Is it ujutro or u jutro?

Use ujutro (one word) for “in the morning.” U jutro is generally not used in this time sense; it can sound odd or overly literal.

Is e-mail the most natural word here? What about email, e-poruka, or e-pošta?

All are understood:

Everyday speech: e-mail or email are very common (both spellings occur; the hyphen isn’t obligatory).
More Croatian-leaning: e-poruka (email message), e-pošta (email as a system/service). In your sentence, pošaljite e-mail is perfectly natural.

How do I say “send it by email,” not “send an email”?

Use the instrumental:

Pošaljite to e-mailom.
Pošaljite dokument e-poštom. Note the difference:
pošaljite e-mail = send an email (a message)
pošaljite [nešto] e-mailom/e-poštom = send something by email

Should Vas be capitalized in Molim vas?

In formal letters/emails, capitalizing the respectful pronoun is common courtesy: Molim Vas. In neutral text, lowercase is fine. Choose based on formality and house style.

Can I drop vas or even molim?

Molim, pošaljite e-mail… is acceptable and still polite.
Pošaljite e-mail… is a bare imperative—direct but not rude in context (tone and relationship matter).
Molim vas is the safest standard polite opener.

How do I say “the email” or “that email” in Croatian without articles?

Use a demonstrative:

taj e-mail (that/the email)
ovaj e-mail (this email) Example: Molim vas, pošaljite taj e-mail sutra ujutro.

How do I pronounce the sentence?

Approximate English-friendly guide:

Molim vas: MOH-leem vahs
pošaljite: poh-SHAH-lee-teh (š = sh; lj ≈ ly)
e-mail: EH-mayl
sutra ujutro: SOO-trah OO-yoo-troh (j = y)

Is there a softer, question-style request?

Yes, very common:

Možete li poslati e-mail sutra ujutro? (Can you send…?)
Biste li mogli poslati e-mail sutra ujutro? (Could you…?—even softer)

Where does the object pronoun go (e.g., “send it”)?

In affirmative imperatives, the clitic follows the verb:

Pošaljite ga sutra ujutro. (Send it tomorrow morning.) In negative imperatives, it comes before the non-finite form:
Nemojte ga slati sutra ujutro.